A manufactured web material that may be any sheet-like material having a fixed dimension in one direction and either a predetermined or indeterminate length in the orthogonal direction. Examples of web materials include, but are not limited to, metals, paper, wovens, non-wovens, glass, polymeric films, flexible circuits or combinations thereof. Metals may include such materials as steel or aluminum. Wovens generally include various fabrics. Non-wovens include materials, such as paper, filter media, or insulating material. Films include, for example, clear and opaque polymeric films including laminates and coated films.
Web manufacturing processes typically utilize continuous feed manufacturing systems, such as manufacturing systems used to produce paper, film, tape, and the like, and often include one or more motor-driven rotatable mechanical components, such as rollers, casting wheels, pulleys, gears, pull rollers, extruders, gear pumps, and the like. These systems often include electronic controllers that output control signals to engage the motors and drive the web at pre-determined speeds.
When manufacturing web based products that require down-web or cross-web alignment of features on each side of the web, it is important to carefully manage the cross-web and down-web positions, as well as the web strain, to control proper feature alignment. Existing web control strategies to manage these parameters may be limited by the quality of a measurement that provides position feedback to the web control system to maintain the relative alignment of web features.